Off the top of my head:
tung oil (pure, not polymer!)
walnut oil, as mentioned
beeswax
Also, you can look around for salad bowl oils to finish. Or, just go to your friendly neighborhood hardware store, and tell them you need a non-toxic food-safe finish. Some finishes may contain hardners which evaporate as the product dries, and will be safe for food surfaces according to the FDA, but I will leave that judgement up to you.